Crustal structure of the Madeira-Tore Rise, eastern North Atlantic—results of a DOBS wide-angle and normal incidence seismic experiment in the Josephine Seamount region
Crustal structure of the Madeira-Tore Rise, eastern North Atlantic—results of a DOBS wide-angle and normal incidence seismic experiment in the Josephine Seamount region
复制标题
北大西洋东部马德拉-托雷隆起的地壳结构——约瑟芬海山地区 DOBS 广角和正入射地震实验的结果
DOI：
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发表时间：
1991
期刊：
影响因子：
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通讯作者：
P. Barton
中科院分区：
文献类型：
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作者：
C. Peirce;P. Barton
总结
1988年11月至12月期间，在约瑟芬海山收集了大量的地球物理数据集，约瑟芬海山位于北大西洋东部马德拉-托尔海隆东北端。约瑟芬海山位于马德拉-托尔海隆和亚速尔-直布罗陀断裂带的交汇处，后者代表北大西洋东部这一部分的非洲-欧亚板块边界。根据这一数据集，一条275公里长的爆炸折射线连同广角气枪剖面、地震反射和重力数据一起被模拟出来。速度-深度模型显示，海山两侧的地壳具有典型的海洋性。然而，在海山之下，存在一个异常高速和地壳增厚的区域，深度约为17-18公里。重力模型还表明，约瑟芬海山受到地壳根的补偿，约瑟芬海山/马德拉-托尔海隆系统处于局部均衡状态。在这个地区的岩石圈的抗弯刚度和有效弹性厚度的计算表明，Madeira-Tore隆起形成的岩石圈上，它的同时。这一地壳负荷年龄与马德拉-托雷海隆是在大西洋中脊或其附近形成的海隆的假设是一致的。
SUMMARY
During November–December 1988, an extensive geophysical data set was collected over the Josephine Seamount, which is located at the northeasterly end of the Madeira–Tore Rise in the eastern North Atlantic. The Josephine Seamount lies at the intersection of the Madeira–Tore Rise and Azores–Gibraltar Fracture Zone, the latter representing the Africa–Eurasia plate boundary in this part of the eastern North Atlantic. From this data set, a 275 km long explosive refraction line has been modelled together with wide-angle airgun profiles, seismic reflection and gravity data. The velocity–depth model shows that the crust either side of the Seamount is typically oceanic in character. However, beneath the Seamount there exists a region of anomalously high velocity and crustal thickening to a depth of about 17–18 km. Gravity modelling also suggests that the Josephine Seamount is compensated by a crustal root, and that the Josephine Seamount/Madeira–Tore Rise system is in local isostatic equilibrium. Calculations of the flexural rigidity and effective elastic thickness of the lithosphere in this region suggest that the Madeira–Tore Rise formed contemporaneously with the lithosphere on which it lies. This age of crustal loading is consistent with the proposal that the Madeira–Tore Rise is an aseismic ridge which formed at or near the Mid-Atlantic Ridge.